Cutaneous ciliated cyst in a 16-year-old girl.

A 16-year-old girl was seen for a painless subcutaneous mass of 1 year's duration. On excisional biopsy, a collapsed cystic structure lined by stratified, ciliated, columnar epithelium was noted; findings were consistent with cutaneous ciliated cyst. Immunohistochemical staining for progesterone receptor and epithelial membrane antigen were positive, whereas it was negative for carcinoembryonic antigen, which supports the theory of heteropia of the ciliated epithelium from the Müllerian epithelium in its histopathogenesis.